The terminology ‘servicing field devices’ means, the configuring and parametering of field devices, but includes, however, also, diagnosis for the purpose of early detection of defects in one or more field devices or in the process. Besides the remote servicing of a field device from a remote terminal, any type of information transfer is furthermore understood under the term ‘servicing’. The focus in this context is on the transfer of the parametering of the field device from the field device to the remote terminal as well as the playback of the parametering of the field device by the remote terminal to the field device. As well as the parametering of the field device, the generation of a print version for the purpose of printing by a printer is likewise understood under ‘servicing’. In general, the remote terminal is understood to be, for example, a PC, a configuration/management system, for example, the configuration tool FieldCare, which is made and sold by the assignee, or a handheld device of any kind. Field devices serving to register and/or influence process variables are often applied in process automation technology as well as in manufacturing automation technology. Measuring devices such as, for example, fill level measuring devices, flow measuring devices, pressure and temperature measuring devices, pH measuring devices, conductivity measuring devices, etc., which register the corresponding process variables fill level, flow, pressure, temperature, pH value, or conductivity serve to register process variables. Actuators, such as valves or pumps, via which e.g. the flow of a liquid in a pipeline or the fill level of a medium in a container is changed, are used to influence the process variables. In principle, all devices, which are applied near to the process and deliver or process information relevant to the process, are referred to as field devices. A large number of such field devices are available from the Endress+Hauser group of companies. Thus, all types of measuring devices and actuators are subsumed under the term field device used in connection with the invention. Furthermore, the term field device also means e.g. a gateway, a radio adapter or other bus participant integrated/integrable in a bus system.
In modern industrial plants field devices are, as a rule, connected to at least one superordinated control unit via bus systems such as, for example, Profibus® PA, Foundation Fieldbus® or HART®. Normally, the superordinated control unit, as already mentioned, is a control system or a control unit specified in detail earlier. The superordinated control unit serves for process control, process visualizing, process monitoring as well as for the start up and servicing of the field devices. Programs for such purposes run independently in superordinated units and include, for example, the FieldCare tool of the Endress+Hauser group of companies, the Pactware tool, the AMS tool of Fisher-Rosemount or the PDM tool of Siemens. Servicing tools integrated in control system applications include PCS7 of Siemens, Symphony of ABB and Delta V of Emerson.
The integration of field devices in configuration systems or management systems or superordinated control units occurs via device descriptions, which ensure that the superordinated units can detect and interpret the information delivered by the field devices. The device descriptions for each field device type or for different applications of each field device type are provided by the respective device manufacturer. Different device descriptions must be created for the different fieldbuses so that the field devices can be integrated in different fieldbus systems. Thus there are HART device descriptions, Fieldbus Foundation device descriptions and Profibus device descriptions, just to name a few examples.
For the purpose of creating a unitary description for the field devices, the Fieldbus Foundation (FF), the HART Communication Foundation (HCF) and the Profibus Nutzerorganisation (PNO) have created a unified electronic device description (Electronic Device Description EDD). The EDD is defined in standard IEC 61804-2.
Moreover, particular device descriptions, so called DTMs—Device Type Managers, or device managers, or device drivers for comprehensive servicing of the field devices are obtainable. These DTMs correspond to the FDT—Field Device Tool—specification. Each current FDT specification is available from ZVEI, PNO, or the FDT Group.
Many field device manufacturers already deliver the corresponding DTMs or device descriptions with their field devices. The DTMs encapsulate all device specific data, functions and servicing rules, such as e.g. the device structure, the available communication possibilities and the graphical user interface, i.e GUI, for a given field device or for a given field device type.
DTMs require a frame application, here an FDT frame, as a runtime environment. The frame application and the corresponding DTMs permit a very convenient access to field devices, e.g. to device parameters, measured values, diagnostic information, status information, etc., as well as the invocation of special functions available to individual DTMs. For the DTMs of different manufacturers to correctly function in the frame application, the interfaces to the frame application and the remaining DTMs must be clearly defined. This interface definition is encompassed by the acronym FDT. FDT technology unifies the communication interface between field devices and the superordinated control unit. A special feature of FDT technology is that it functions independently of the installed communication protocol as well as the respective software environment of both the field device as well as the superordinated control unit. FDT enables access to any field device via any superordinated control unit using any protocol. A known FDT frame is the previously mentioned FieldCare of the Endress+Hauser Group.
From the above discussion it can be easily seen that the number of DTMs or device descriptions is very large and that the number of DTMs continually increases due to the continually increasing number of devices and fieldbuses. Consequently, a so called DTM library is often discussed. The effort, which must be spent for the installation of the device driver for the communication hardware, the communication DTMs, the DTMs of the field devices and the software for the frame application, or the FDT servicing software, is very high. Usually, the DTMs are delivered via a separate medium, e.g. on a CD or via the internet, and then installed in the superordinated control unit.
The known solution can lead to problems in the following cases:                A device driver and the current firmware (specific device information from the manufacturer) stored in the field device are not absolutely consistent.        If the current or appropriate device drivers are not present, the field device cannot be integrated in the control system or the superordinated control unit.        The device driver for the previous version is not always compatible with the device driver of a newer device version.        The onsite servicing of the field device is run under a special protocol, with whose help the corresponding information is displayed onsite.        